Sources of P300 attenuation after head injury: single-trial amplitude, latency jitter, and EEG power.

Single trial amplitude, latency jitter, and electroencephalographic (EEG) power were examined as sources of the group difference in averaged P300 amplitude among 15 traumatically brain injured and 20 control individuals in an auditory oddball paradigm. Mean amplitude of the individual trials was highly correlated with the amplitude of the averaged P300, with little additional unique variance attributable to latency jitter or EEG power. The group difference in P300 amplitude was also explained by the mean amplitude of the single trials. These results support the robustness of the evtent-related potential averaging technique within the paradigm used.